Apparatus for surfacing sheet glass



Dec. 17, 1929. J. P. CROWLEY 1,740,006

APPARATUS FOR SURFACING SHEET GLASS Filed May 5, 1924 Patented Dec. 17, 1929 igatooe fics Jos'rzrir I. CROWLEY, or TOLEDO, OHIO, 'AssIGNon'fro'LIBBEYfowEns GL 0F To'L'Eno,oHIo, VACoRPol-:Arieiv or onto 'APPARATUS `ron lSURRACING( `simian en /iss Appucatiaaaied May 5, ie'zi.- 'semanita-710,993.-

This invention relates to improvements yin the lart of making `polished plate glass, and:

loosely side -byside withth'e'ir'adjacent edges f in c'ont'actfupon theatiuppersurface of ay supporting table. Aseriesfofclampingmembersare movably secured to the upper` surface ofthe table, these clampingjmembers outlining between their -inner'ledgesfa shallow recess on thel table Ltop, "which-recess corresponds to v'and is Vslightlylarger.than the area 'off the 'assembled group 'of 'glass plates.

Means are arovidedlforfad'ustind the clam al D ing `members into A'holding Contact 'with-fthe outer exposedt edges ofzt'he groupof' plates so as tofprevent-`-relative movement ofthese plates amongst themselves,`Y or m'ovementf of the group' of plates on the-table top.- 'lhe surfacing'tool isnow-lowered-into place onj the upper exposedsurfaces of the group' of sheets and" thesesurfaces lare "simultaneouslyground or'polished in one continuousfoperation.

The invention willbe more 'clearly-understood Ifrom the following detailed description of one approved'form of the apparatus.

vIn ythe 'accompanying drawings: y s Fig. l is acentral vertical section through a portion of one ofthe. grinding units, this viewbeing taken substantially on theline 1--1v of Fig. 2.

Fig. 2-is a plan vview of the sheet-supportv ing table. p y

Fig. 3 isa lvertical'section through a portion of the table edge on -an enlarged' scale, the view'being taken substantially on the line 3 3 of Fig. 2.

The sheet-supporting table'l is mounted at the. upper end of 4a column' 2 Whieh'turn's in bearings 3' in the viframe-work 4. The table is preferably supported on roller bearings 5 and is positively' rotated `by means of a large bevel gear 6, secured to column 2 and driven through bevel pinion :7 Ona-.driveshaft 8, rotated from any suitable source ot Theftable top 9 1s round, but is adapted to carry upon power such as an electric motor.

itsupper face a group of sheets which'when assembled have an aggregate area-approximately eq `alling that of the largest :square that may be inscribed within th'ecircuinference of the table top. This-tabletopi) r,isconstructedof heavy metal so :as `to kbe absolutely rigid, and-its upperfface is ground asclosely as possible to an absolute plane so as to serve asl a vmaster surfaceonpattern for vthe y glass sheets which "are supported thereon. V

vFourmetalplates l0 are movfablyiinounted on the upper surtace'oftable topf9, so that their'inner edges l1 substantiallyoutline shallow square recess whose bottom is formed by the sheet-suppoi'ting surf-ace ofthe table. Ea'ehplate 10 is'pivoted at one vend tothe top'ofithetable by pivot pin 12,1its other end.

13 4beingadaptedV tofswing toward or lfrom the -center offthe table. fOnly a veryfslight range oit swinging movement is desired 'and` the plateiis `guided during this movement by a. seriesk ofpins or screwsliwhichproject l through :slots 1'5 in the plate-into theltable top 9. Secured to=the innersheet-'engaging edge ofeach plate l0 is a stripfl, oivrubber or other suitable yielding material.

'A sheet-supporting pad 17 ofyielding material7V covers the,` upper lface of=table top 9 within therecess outlined by the lclamping plates 10. Material best adapt/editor this purpose'is cork or cork composition. This pad should be oabsolutely eventhiclzness, so

thaty the master surface ofthe table top-will be repeated on the upper surface of the cork` pad. This pad is of slightly less surface area than the spacebetween the clamping plates so as to allow clearance as shownvat 18,'Fig. 3,

for' the 4movement of the plates'l() toward or fromtheedges ofthe glasssheets 19. The aggregate thickness of the corkl pad. 17 and the glass sheets 19 to be surfaced on this. apparatus Will-.begreater than the thickness ofthe clamping; plateslO,l so that the surface ing tool,` hereinaitery described, will not come centraux.'

into contact with the upper faces of the clamping plate.

A continuous ring having an upper flange 21 and a lower flange 22 engaging the edge portions of the upper and lower surfaces of the ltable top, is slidably mounted arounc the peripheral edge of the table. A. series of four similar cam members 23 are yformed at intervals of 900 along the inner edge of flange 21. Each cam 23 is adapted to bearagainst a cam surface 2e on the outer edge of free end 13 of one of the clamping plates 10. The grinding head 25'is of a standard design, its lower face comprising a series of teet-h or projections 26 which perform the grinding operation on the sheets. While sheets are being placed in or removed from t-he machine this grinding head is elevated above the table, but when in operation the 201 weight of the grinding head rests upon and is entirely supported by the glass sheets 19. Preferably the pivot 27 for the grinding tool turns freely in suitable bearings so that the head 25 is merely an idler and is rotated by the glass sheet. It will be noted that the axis v of rotation of the grinding head is eccentric to the axis of therotating table, and the head is of such diameter that t-he operating face will work upon the corners of the group of sheets as Well as the center thereof.

l/Vhen the machine is stationary and the grinding head 25 is raised, a plurality of glass plates 19 will be laid loosely upon the cork pad 17, as shown in Fig. 2. As here shown, three long and comparatively narrow plates 19 are simultaneously ground, the group of sheets when assembled having a substantially square outline. It is to be understood that this group of' sheets is shown merely by way of example and that any other number, or grouping of sheets or plates might be used, it only being essential that the aggregate area and configuration conform substantially to the recess outlined by the' clamping plates.

When these plates have been placed in position with their inner edges in contact with one another, the operator grasps the ring 2O and shifts it in the direction of arrow 28. This operation slides lthe cams 28 along cam surfaces 24 and moves the free ends 13 of clamps 10 inwardly against the assembled group of glass-sheets. No great.

pressure is required against the sheets, it

merely being essential that the sheets he heldV firmly against relative movement along their engaging edge portions. The grinding tool 25 is now lowered onto the sheets and the table 1 is rotated in the direction of arrow 29. This direction of movement of the table will tend to lock the sheets more firmly in place against the edges of the assembled sheets.

l/Vhen one side of the sheets has been surfaced, the rotation of the table is stopped, the grinding head 25l is raised, and the operator will shift the ring 20 in the direction opposite the arrow 28, or counterclockwise as seen in Fig. 2, thus unlocking the clamping plates 10. The glass sheets may now be removed and turned over, or new lones placed upon the table top.

lVhile an apparatus sheets has here been illustrated and described, it is to be understood that the sheet-sup- 1porting table for a polishing machine could e constructed on much the saine principle.

According to this invention a plurality of sheets, -of the smaller commercial sizes, may be simultaneously surfaced, quicklyrand efficiently, with a large saving of time and expense as compared with the old method of separately securing the individual sheets in place upon the supporting surface of the table byembedding each sheet in plaster of Paris.

T claim V1. 1n an apparatus for vsurfacing sheet glass, a round sheet-supporting table having a fiat upper sheet-supporting surface, a plurality of clamping members movablymounted -on the table top adjacent the edges of the sheet-supporting surface, a ring slidably mounted on the peripheral edge of the table, and a series of cams carried by the ring and bearing against the outer edges of the clamps ing members. l

2. InV an apparatus for surfacing sheet, glass, a round sheet-supporting table having a flat rupper sheet-supporting surface, a plurality of clamping members grouped around thesupportiiig surface, each member pivoted at one end t-o the table-top, a ring slidably mounted on the peripheral edge of the table, and a series of cams carried by the ring and'bearing against the outer free ends of the clamping members.

3. In an apparatus for surfacing sheet glass, a table having a flat upper sheet-sup- Y porting surface, a plurality of clamping mem` bers movably mounted on the table-top adjacent to and delining the edges of the sheetsupporting surface, a cani member behind each clamping member, and means for simultaneously moving the cams to shift the clamping members into engagement withv the glass sheets on the supporting surface.

4.-. In an apparatus for surfacing sheet glass, a sheet supporting table having a sheet-` supporting surface, a pluralityv of clamping members varranged 0n said supporting surface, and each pivoted thereto, a member'slidably mounted peripherally of said table andV a plurality of cams carried by said member and engaging the free ends of said clamping members. f Signed at Toledo, in the county of ALucas and State of Ohio, this 1st day of May, 1924.

Y JOSEPH P. CROWLEY;

for grinding. the glass 

